Ducted gas turbine engines are designed to enable a stream of cold air from the fan to pass through a channel formed by a duct between the casing of the engine and outer ducting or cowling. It is known to provide ducted fan gas turbines with means for deflecting this by-pass flow of air so as to assist in braking of an aircraft on which the engine is mounted. Such thrust reversing means are designed in various forms. One prior art proposal is to provide a plurality of doors which are translatable into positions which block the by-pass air. A plurality of deflector vanes are provided within cowling which is uncovered when the thrust reverser is in the deployed position. Thus the fan exhaust air is directed generally radially outward and partially forward by the deflector vanes to provide braking.
It is important to provide access to gas turbine engines so that maintenance and inspection of parts can be conducted. One method of allowing access is to provide doors within the engine casing. These doors are generally C shaped and hinged at a location adjacent the pylon from which the engine is mounted on the aeroplane. One main problem with such doors is that because they form part of the actual casing of the engine, the coupling is inherently heavy and complicated. Also, because of the weight of the doors, hydraulic jacks are normally employed to control movement of the doors. Such C ducts must also be designed to accommodate the space requirements of thrust reversers. Such an arrangement is disclosed in prior patent GB1,304,212 and GB2,045,179 among others.
Another method of providing access to ducted, large by-pass gas turbines has been by actual entry into the ducting by the maintenance crew. However on some engines the by-pass areas have been reduced and the area is not large enough to allow access.